Devices for storing and providing electrical power have been in use for a long time. Generally falling under the descriptor “battery,” such devices include electro-chemical cells and collections of cells that provide an electrical potential between at least a set of terminals. The terminals can be connected to an electrical (e.g. direct current, DC) load to energize or power the load. Batteries include dry cells, wet cells (e.g. lead-acid cells), and other types of units that generally convert a chemically available electromotive force into a current.
Batteries are sometimes classified into “primary” and “secondary” types. Primary batteries are single-use units that come from a manufacturer with a limited electrochemical capacity and are exhausted and discarded after use. Secondary batteries can be “recharged” after use, and while not infinite in their capacity, allow for repeated use of the same cell through reversing the discharge process to some extent.
To increase battery capacity, cells have been configured to take advantage of a large surface area between the anode (negative) and cathode (positive) elements of the cells. One such design involves placing many parallel plates in electrolyte solution to allow for ionic transfer between the anodes and cathodes. Another design separates planar layered sheets of anode and cathode materials with porous membranes, then rolls the layers into a roll, referred to as a “jelly roll” that provides a compact and mechanically stable battery. In rolled battery designs, multiple alternating sheets of anode, separator, and cathode materials are used as permitted by the spatial considerations of the battery, and the anode sheets are collectively connected to an anode terminal while the cathode sheets are collectively connected to a cathode terminal. The device may be rolled cylindrically or in other geometries, knows as prismatic configurations.
The entire device is packaged in a rigid enclosure, usually a cylindrical can. The anode and cathode materials and terminals are prevented from making electrical contact to avoid short-circuiting or discharging the battery except through the intended terminals through an electrical load connected thereto.
One problem encountered in traditional battery designs is that of the electrical impedance of the battery itself, which causes loss of electrical power and dissipation of heat internally within the battery. Another problem with present battery designs is that the ends of the cells are not well integrated into the anode and cathode terminals usually found at either end of a cylindrical battery design. Yet another deficiency of present battery designs is their inability to provide good thermal response and heat sink capabilities, especially in high-power applications. Additionally, present battery designs using collector sheets have not been successful in providing a way to connect a plurality of anode or cathode collectors together.